KLR Wheels are beyond simple to take off and I should be holding a wrench about as much as a monkey should.
I find it much easier to remove the brake calipers first, just a couple of quick bolts and walla, get them out of the way. You can do the wheels without removing the calipers, but the two bolts are much easier to deal with then trying to slot the rotor back in later. Get a small piece of something as thick as the rotor to slide between the brake pads.
Take any cotter pins out and start wrenching. It's as easy as that.
Heck, unless the dealer is mounting them for free or dirt cheap, I would do the tires yourself so you know how to when your in the field later with a flat tire. It's not difficult, the key is... if it's making you cuss, swear and piss blood... your doing it wrong.
This is a three part series that applies very well to the KLR.
Going back on, grease everything, make sure the gear is through the chain, slide the axle through, start wrenching till it's close. Line up the site lines on the frame, wrench it down, throw in the cotterpins and walla... wheels are back in place. Throw the calipers back in place and your all done!
If I can do it..... let's just say you stand a chance if you know what a wrench is. Get some tire irons... I never heard of these till I had KLR. I've changed several tires now and each time it gets easier. Again, your hearing this from a mechanically challenged person, so believe me, you can do it and you'll thank yourself next time your out and about with a flat.